Biomass is conventionally viewed as a promising feedstock for producing automobile fuels and petrochemical feedstocks from the viewpoint of energy security and reduction of the amount of carbon dioxide. A number of attempts have been made so far to use biomass as a fuel oil for automobiles, etc. For example, Patent Documents 1 to 5 listed below disclose methods of using biomass, such as vegetable oil and animal fat, as diesel engine fuel after mixing with mineral oil.
However, as described in the aforementioned Patent Documents 1 to 5, when biomass is simply mixed with mineral oil, the fuel obtained has poor stability because of the unsaturated bonds and oxygen present in the biomass, which makes it difficult to manage. Besides, these components pose the risk of adversely affecting the materials used in automobiles.
On the other hand, Patent Document 6 listed below discloses a method of producing gasoline by bringing together a higher fatty acid glycerol ester and a zeolite-containing catalyst.    Patent Document 1: Japanese Patent Laid-Open No. 61-57686    Patent Document 2: National Publication of International Patent Application No. 1994-510804    Patent Document 3: Japanese Patent Laid-Open No. 07-82576    Patent Document 4: Japanese Patent Laid-Open No. 08-41468    Patent Document 5: Japanese Patent Laid-Open No. 10-152687    Patent Document 6: Japanese Patent Laid-Open No. 59-62694